I recently saw Redmine use Rails 5.2.1, which is a good thing.

However, upgrading to Rails 5.2.1 does not simply add it to the Gemfile.

I have migrated the migration files from 4.2 to 5.2, please consider the patch.

The reason for the change: The default id of Rails 3-4 is int, which allows for a maximum of 4.2 billion items.

This is not a big number when using Redmine in large-scale applications.

Need to replace with bigint(20) in id and foreign key.

I tested the patch and confirmed that Redmine works normally after the upgrade.